How can I ease my mum into letting me wear make-up?

I am 13 nearly 14 and I want to start wearing make-up. (Just powder foundation, mascara ect.) I am the youngest of 6 (all girls) so i guess my mum would be used to it by now. But I don't want to suddenly just come down the stairs one day all dolled up (She probably wouldn't let me wear too much.) Thanks for reading. :D xx